Glue jig to position adhesive-applied specimens

ABSTRACT

A jig is provided for setting and gluing pairs of specimens along their joining faces to cure into a lap joint. The jig includes a platform with a setting surface flanked by first and second upright walls, first and second plates and fasteners. The platform positions the pairs of specimens for lap joint arrangement.

STATEMENT OF GOVERNMENT INTEREST

The invention described was made in the performance of official dutiesby one or more employees of the Department of the Navy, and thus, theinvention herein may be manufactured, used or licensed by or for theGovernment of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

BACKGROUND

The invention relates generally to a glue jig for setting specimens orcoupons to be adhesively bonded. In particular, the glue jig enablesseveral specimens to be arranged for concurrent joint arranging andcuring.

Specimens or coupons can be attached together for material responsetesting to measure strength and shear modulus of the bond. The lap jointrepresents one such configuration, and this can be achieved for selectmaterials by chemical adhesive or glue.

SUMMARY

Conventional glue jigs yield disadvantages addressed by variousexemplary embodiments of the present invention. In particular, variousexemplary embodiments provide expansion in number of joints to beproduced concurrently. Improved repeatability and scalability inestablishing such joints over an extended curing interval represents anobjective for the embodiments described in this disclosure.

Various exemplary embodiments provide a jig for setting and gluing pairsof specimens along their joining faces to cure into a lap joint. The jigincludes a platform with a setting surface flanked by first and secondupright walls, first and second plates and fasteners. The platformpositions the pairs of specimens for lap joint arrangement. The settingsurface has a plurality of orifices disposed along the pairs ofspecimens.

The orifices are disposed along a longitudinal non-joining face, alateral non-joining face, or a corner of adjacent specimens. The firstand second plates are fastened respectively adjacent said first andsecond upright walls opposite the setting surface with the fasteners totighten the plates to the upright walls. The pins are inserted intocorresponding orifices to retain the pair of specimens along theirnon-joining faces from translation along the setting surface.

The plurality of pins includes retainer pins along said longitudinalnon- joining face, alignment pins along said lateral non-joining face,and stop pins at said corners of adjacent pairs of specimens. The platesinclude threaded orifices through which to insert the fasteners.

BRIEF DESCRIPTION OF THE DRAWINGS

These and various other features and aspects of various exemplaryembodiments will be readily understood with reference to the followingdetailed description taken in conjunction with the accompanyingdrawings, in which like or similar numbers are used throughout, and inwhich:

FIG. 1 is a plan schematic view of a glue jig;

FIG. 2 is a perspective view of the glue jig with adhered components;and

FIG. 3 is a plan view of a glue joint fusing two specimens.

DETAILED DESCRIPTION

In the following detailed description of exemplary embodiments of theinvention, reference is made to the accompanying drawings that form apart hereof, and in which is shown by way of illustration specificexemplary embodiments in which the invention may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilized,and logical, mechanical, and other changes may be made without departingfrom the spirit or scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the present invention is defined only by the appendedclaims.

FIG. 1 shows a plan schematic view 100 of a glue jig. The jig restrainsspecimens for fusing together using adhesive, such as glue. Theexemplary configuration described corresponds to a single lap joint,although artisans of ordinary skill will recognize other configurationscan be contemplated without departing from the scope of the invention.

The glue jig includes an upper side plate 110 and a lower side plate 115to constrain a jig box 120. Both plates 110, 115 are removable uponcomplete curing of the adhesive. A set of thumb nuts 130 secures theplates 110, 115 to the box 120 to inhibit lateral movement. The plates110, 115 include holes passing therethrough, with screw threadsextending half-way through the thickness from outward to inward.Tightening the nuts 130 enables the plates 110, 115 to hold the box 120in compression. The box includes a setting platform on which thespecimens are positioned for gluing together, and bounded by uprightwalls. Some specimens can be disposed to abut either wall.

The box 120 uses retaining pins 140 for specimen disposition along theirlongitudinal axes as well as glue alignment pins 145 for specimendisposition along their lateral axes. Stop pins 150 restrict thespecimens at their corners, for example where specimens abut each otherThe pins 140, 145, 150 are secured to the box 120 by orifices drilledthrough its bottom face and are disposed upright therein. These orificescorrespond to the same diameter as their respective pins.

The schematic view 100 shows four specimens: first 160, second 165,third 170 and fourth 175. The initial alignment pins 140 restrain thespecimens from lateral translation, whereas the glue alignment pins 145restrict longitudinal sliding. The specimens 160, 165, 170, 175 aredisposed with one edge (or wall) facing the jig box. Adhesive regions180, identified by dash ovals, correspond to the interfacing surfaces ofthe specimens to be glued together.

As shown, upper and lower lap joints provide an example configuration,although the box 120 is not limited thereto. The third sample 170,adjacent the upper plate 110, adheres to the first sample 160. Thefourth sample 175 adheres to the second sample 165 adjacent the lowerplate 115.

The glue jig is designed for Tensile-Lap Adhesive Specimen Preparationfor reproducible production of tensile-lap thick specimens to measurestrength and shear modulus of non-rigid adhesives. This preparationconforms to ASTM D3983-98, Standard Test Method for Measuring Strengthand Shear Modulus of Non-rigid Adhesives by the Thick-AdherendTensile-Lap Specimen.

Exemplary embodiments of the glue jig were developed due to restraintsimposed by 1) specimen specific preparation requirements and 2)available testing equipment. The glue jig, for the configurationdescribed, can hold two pairs of specimens in place for correspondingpairs of lap joints during cure interval. However, this depictedarrangement is not limiting being extendible to additional specimens,and/or alternate types of joints. Removable side plates 110, 115 andretaining pins 140, 145, 150 facilitate use of the jig. The metal frameis readily oiled with spray to inhibit undesired sticking if any glue isspilled on parts not intended to form the glue joint.

FIG. 2 shows a perspective view 200 of the jig box 120 with a pair ofsingle lap joints adhering pairs of specimens. Excess glue 210 escapesfrom the joint regions 180 after squeezing the specimens together fordesired separation.

FIG. 3 shows a plan view 300 of a glue joint fusing two specimens.Removal of the excess glue shows a single lap joint 310 (within thejoint region 180) to securely attach the first and third specimens 160,170 together

Procedures for use can be generalized as follows: First, place the firstand second specimens 160, 165 as metal test parts with dimensions2″×0.25″×0.300″ into the center of the box 120 of the glue jig so thatone end of each specimen rests against the stop pins 150.

Second, for the upper half, deposit appropriate amount of glue on thefirst specimen 160 as well as the third specimen 170 against thealignment pin 140. Third, gently tighten the side plate thumb screws130. This tightens the first specimen 160 to the third specimen 170,thereby leaving a glue line thickness of 0.060″ by 0.750″ length.

Fourth, repeat this process for the lower half of the Glue Jig with thesecond and fourth specimens 165, 175. After a suitable post-cure period,remove the pins 140, 145, 150 from the glue jig box 120 and gentlyremove the test specimens 160, 165, 170, 175 and trim the excess glue210 from the edges and ends with an appropriate knife.

The development of this glue jig provides several advantages over theglue jig in the ASTM standard. For a single lap joint, two or morespecimens can be cured in the same jig. The joints can be reproduciblefor preparing and comparing multiple sets of specimens. Removableretaining pins 140, 145, 150 facilitate removal of test specimen 160,165, 170, 175 without prying, preventing damage to the glue joint 310.Metal parts to be adhered in this manner can tolerate heat loads duringadhesive cure multiple times and are thus less vulnerable to warp orother distortion. This type of jig can be manufactured in any size tofit a wide variety of applications.

While certain features of the embodiments of the invention have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art. Itis, therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the embodiments.

1. A jig for setting and gluing pairs of specimens along their joiningfaces to cure into a lap joint, said jig comprising: a platform forcontaining the pairs of specimens, said platform including a settingsurface flanked by first and second upright walls, the specimens beingdisposable on said setting surface parallel to each other and partiallyoverlapping to form the pairs for lap joint arrangement along thejoining faces, said setting surface having a plurality of orificesdisposed along the pairs of specimens, each orifice of said plurality oforifices being disposed at one of along a longitudinal non-joining face,a lateral non-joining face, and a corner of adjacent specimens; firstand second plates respectively adjacent and parallel to said first andsecond upright walls opposite said setting surface; fasteners fortightening said plates to said upright walls; a plurality of pins forinserting upright into corresponding orifices of said plurality oforifices to retain the pair of specimens along said non-joining facesfrom translation along said setting surface.
 2. The jig according toclaim 1, wherein said plurality of pins includes retainer pins alongsaid longitudinal non-joining face, alignment pins along said lateralnon-joining face, and stop pins at said corners of adjacent pairs ofspecimens.
 3. The jig according to claim 1, wherein said plates includethreaded orifices through which to insert said fasteners.